Electrical connection and method of making the same



May 30, 1967 M. POLIDORI 3,322,887

ELECTRICAL CONNECTION AND METHOD OF MAKING THE SAME Filed June 22, 1964 3 Sheets-Sheet 1 INVENTOR. 2 MARIO POLIDORl May 30, 1967 M. POLIDORI ELECTRICAL CONNECTION AND METHOD OF MAKING THE SAME 3 Sheets-Sheet 2 Filed June 22, 1964 INVENTOR. MAEIO POLl DOP\ yww May 30, 1967 M. POLIDORI. I 3,32

' ELECTRICAL CONNECTION AND METHOD OF MAKING THE SAME Filed June 22, 1964 3 Sheets-Sheet 5 INVENTOR. MARIO, POLIDORI United States Patent 3,322,887 ELECTRICAL CONNECTION AND METHOD OF MAKING THE SAME Mario Polidori, Pennsauken, N.J., assiguor to AMP Incorporated, Harrisburg, Pa. Filed June 22, 1964, Ser. No. 376,941 6 Claims. (Cl. 17494) This invention relates to crimped electrical connections, and more particularly to connector elements and tools for the formation thereof. In the formation of electrical connections, it is customaryto enclose wire ends in an electrically-conductive metal ferrule. The present invention discloses this type of connector element which simultaneously grips a support means after it has been mechanically and electrically compressed onto wires by a suitable crimping tool.

A spring leaf is used to bias carbon armature brushes against a commutator. One surface of the connector element presses against the brush so that current-is carried from the armature through the brush to the connector element and subsequently to the wire.

In the art of armature-brush rigging, and particularly to brushes which are radially applied to the commutator, the brush rigging must fulfill the followingrequirements:

l) The brushes must be held firmly against the commutator by a spring member (spring leaf and connector element in this case) but allowed to follow any irregularity in the contour of the commutator without jumping awa I (2 All of the parts involved must be firm and strong so that the brushes will not chatter as a result of excessive vibrations while the machine is running.

1 (3) The connector element must'be capable of remaining mechanically tight at all times although therefis a differential in the expansion of steel and the metal of the connector element during temperature changes.

It is, therefore, a primary objective of the present invention to provide a connector element which is capable of being cold-forged onto a spring leaf support means with at least one solid or stranded conductor wire compressed therebetween. A further object is the provision of a connection whereby a softer connector element will deform around a harder support means as a result of crimping pressures from a tool. Another object is to provide a connection having large contact surfaces between the crimped ferrule and the spring leaf so that the ferrule will frictionally engage the spring leaf and give added tensile strength to the connection. Another object is that of providing the combination of a closed ferrule connector element, large surface engaging area, and a cold-forged connection. Another object is to providea tool head and die set for crimping the electrical connector. Another object is to provide a die set for crimping the electrical connector, which attaches to a scissor action tool head and which closes onto the connector element in a straight-line path. Another object is to provide a new method for obtaining an electrical connection.

Other objects and attainments of the present invention will become apparent to those skilled in the art upon a reading of the following detailed description when taken in conjunction with the drawings in which there is shown and described an illustrative embodiment of-the invention; it is to be understood, however, that this embodiment is not intended to be exhaustive nor limiting of the invention but is given for purposes of illustration and principles thereof and the manner of applying it in practical use so that they may modify it in various forms, each as may be best suited to the conditions of a particular use.

FIGURE 1 is a perspective view of a connection, according to the present invention;

FIGURE 2 is a perspective view of the head of a crimping tool which forms the connection of FIGURE 1;

FIGURE 3 is a view of the present tool head in position in a tool;

FIGURE 4 is a top plan view of the connection of FIGURE 1;

FIGURE 5 is a side elevational view of the connection of FIGURE 1 in engagement with a brush;

FIGURE 6 is an end view of FIGURE 4;

FIGURE 7 is an exploded perspective view of the connection elements before crimping;

FIGURE 8 is a side elevational view of the tool head in the open position; and

FIGURE 9 is a view similar to that of FIGURE 8 but showing the tool head closed.

Referring now to the drawings and particularly to FIGURE 7, the connector element includes a closed rectangular-shaped ferrule 2 formed from electricallyconductive malleable metal, such as, copper, an alloy thereof, or the like. It may be rolled up from a sheet metal blank with its seam brazed, it may be reformed from cylindrical tubing, or it may be formed in any suitable and conventional manner. Ferrule 2 has a passageway 4 therethrough to receive a wire 6 and a spring leaf 8.

Compacting or crimping of the ferrule 2, spring leaf 8 and wires 6 is accomplished by a die set D which includes an indenter 10 and a nest 12. Die set D is appropriately affixed to headH Of a preferably air operated tool T, FIGURE 3, of the type completely shown and described in US. Patent No. 2,684,003, which is assigned to the present assignee. While an air or hydraulic-actuated tool is preferable in this case because of excessive crimping'pressures needed and because of production line techniques, it should be noted that head H may be adapted to fit into a manually-operated tool of the type shown and described in US. patent application Ser. No. 420,586 filed Dec. 23, 1964, and assigned to the present assignee. Indenter 10 and nest 12 close onto ferrule 2 in a straightline path (straight action), FIGURE 2, as opposed to the normal arcuate path (scissor action) of a scissor action tool.

Nest 12 constitutes one-half of the die set and includes a floor surface 14 onto which the connector element rests in the tool. On one end of floor 14 is a locating block 16 and another locating block 18 as best seen in FIGURE 8. Ferrule 2 abuts block 16 and the end of the spring leaf 8 abuts block 18 when they are placed into the die set to be crimped in order to properly locate the ferrule along spring leaf 8.

Two crimping members 20 are positioned along each side of floor 14 in diametrical relationship and they extend URES l, 4, 5 and 6. Nest 12 has arcuate-shaped slots 30 and 32 below floor 14 through which a pin 33 passes in order to hold the nest on tool head H. Nest 12 also has two guide posts 34 and 36, the extending ends of which slidably project through corresponding holes in indenter as shown.

Indenter 10 constitutes the other half of die set D and is pinned to the upper jaw of the tool head H by means of a pin 38 passing through arcuate-shaped slots 40 and 41 in a manner similar to that of slots 30, 32 and pin 33. Indenter 10 is located in diametrical relationship with respect to nest 12 and is positioned with respect thereto by means of guide posts 34 and 36. Indenter 10 includes a rectangular member 42 longitudinally disposed in its central section as illustrated in FIGURES 8 and9. Member 42 engages the top surface of ferrule 2 and compresses that portion of the ferrule onto the wires and spring leaf during crimping.

Three outwardly extending crimping members 44 with angled surfaces 44' thereon are positioned along each side of the crimping areas of indenter 10 and they are alter nately spaced with respect to crimping members on adjacent nest 12. During crimping, members 20 and members 44 indent ferrule 2 along opposite sides thereof in a staggered manner. The indenting line of force is at right angles to the longitudinal axis of ferrule 2 because of the straight-line die action.

The indenter and nest are converted from scissor action to straight-line action by means of the pin 33 and slots 30 and 32 of the nest and pin 38 and slots 40 and 41 of the indenter in conjunction with guide posts 34 and 36. Surfaces 56 of indenter 10 engage surfaces 58 of nest 12 when the die set has been moved to its closed position in order to limit the movement of these elements toward each other.

Operation.--Spring leaf 8 and wires 6 are inserted into ferrule 2 in the manner shown by FIGURES l and 7. Wires 6 are positioned so that their forward ends are appropriately spaced from the front of spring leaf 8. This sub-assembly is placed into die set D so that lower forward edge 46 of ferrule 2 abuts locating block 16 and forward edge 48 of spring leaf 8 abuts locating block 18. The connection elements are now positioned in the die set D for crimping.

As the tool closes onto the connector element, rectangular member 42 on indentor 10 pushes the ferrule downwardly against nest 12. At this time, the angled surfaces 44 on crimping member 44 engage the top edges of ferrule 2 and compress the ferrule downwardly and inwardly in areas 50 as illustrated in FIGURES 1 and 6. As indenter 10 bottoms into nest 12, angled surfaces 20' on crimping members 20 engage opposite edges of ferrule 2 in staggered relationship to crimping members 44. Crimping members 20 push areas 22, 24, 26 and 28 of ferrule 2 upwardly and inwardly towards the spring leaf as illustrated in FIGURE 4.

The forces of crimping members 20 and 44 in conjunction with the crimping forces from rectangular member 42 and floor 14 compress ferrule 2 onto wires 6 and spring leaf 8. These combined forces also cause the top surface of ferrule 2 to bow inwardly as at 54, FIGURE 1 and 6, and thereby tighten the ferrule onto the wires and spring leaf to effect an excellent mechanical and electrical connection.

The above crimping action causes large interfaces to occur between the connector element and the spring leaf at the top and bottom thereof and interfacial angles between the inside of ferrule 2 and the edges of spring leaf 8. By this means, the ferrule is frictionally held onto the spring leaf especially when the material of the spring leaf is harder than that of the ferrule.

The above crimp features in conjuction with a closed ferrule will cause the ferrule to tighten onto the spring leaf when the connector element is subjected to temperature changes, even though there is a differential of expansion between steel and the metal of the ferrule.

In cases where the material of the spring leaf 8 is capable of being indented, crimped areas 22, 24, 26, 28'

however, it should be emphasized that the particular embodiment of the invention, which is shown and described herein, is intended as merely illustrative and not as restrictive of the invention.

What is claimed is:

1. An electrical connection comprising a flat support member of substantially rectangular cross-sectional configuration and of substantially hard metal having spring characteristics, a ferrule member of substantially softer metal than said sup-port member, conductor means dis posed between one surface of said support member and an opposing surface of said ferrule member, said ferrule member being in engagement with said support member along another surface and sides of said support member with said one surface of said support member and said opposing surface of said ferrule member being directed toward each other thereby securing said conductor means therebetween, a plurality of spaced depressions along each side of said ferrule member, and another plurality of spaced depressions along each side of said ferrule member between the first-mentioned plurality of spaced depressions, said spaced depressions being directed inwardly toward said sides of said support member thereby securing said ferrule member on said support member.

2. An electrical connection according to claim 1 wherein said opposing surface of said ferrule member has an inwardly-directed arcuate configuration.

3. An electrical connection according to claim 1 wherein planes of said first-mentioned plurality of spaced projections in each side intersect with planes of said other plurality of spaced projections.

4. An electrical connection comprising a flat support member having a substantially rectangular cross-section and provided with a first surface, a second surface and opposing sides, an electrical conductor means having a first portion and a second portion, said first portion being in engagement with said first surface, and a ferrule member having a first section in snug engagement along said second surface, side sections extending along respective sides and a second section extending inwardly toward said first surface and securing said first portion of said conductor means therebetween with said second portion extending outwardly from said first portion, said side sections having first and second depressions at spaced intervals therealong with said second depressions "being disposed between said first depressions, said depressions being directed inwardly toward said opposing sides of said support member thereby securing said ferrule member on said support member.

5. A method of making an electrical connection between a readily deformable metallic ferrule member of rectangular cross section and a wire means onto a flat support member of springy hard metal; the method comprising the steps of placing the ferrule member on the support member with the wire means disposed between opposing surfaces of said support member and said ferrule member; applying controlled pressure to opposing sections and sides of said ferrule member; pressing the opposing sections inwardly toward respective surfaces of said support member with one of said sections extending along and in engagement with one of said surfaces and the other of said sections pushing said wire means into engagement with the other of said surfaces, and pressing spaced areas of said sides of said ferrule member into securing engagement with respective sides of said support member without deforming said support member.

6. A method of securing a readily deformable metallic ferrule member of rectangular cross section onto a flat References Cited support member of springy hard metal comprising the UNITED STATES PATENTS steps of placing said ferrule member on said support member; applying controlled pressure to the top, bottom and 2724098 55 j' 339 276 sides of said ferrule member; pressing said top and bottom 5 3015683 1/1962 OKeefe et I'M-"84 inwardly toward and into engagement with opposing sur- FOREIGN PATENTS faces of said support member, and pressing said sides in- 688,708 3/1953 Great Britain wardly at spaced locations thereby pressing these loca- 95 8 [1953 Great Britain tions into engagement with opposing sides of said support member to secure said ferrule member on said support 10 LEWIS MYERS Prlmary Examinerme mber with-out deforming said support member. D. L. CLAY, Assistant Examiner. 

4. AN ELECTRICAL CONNECTION COMPRISING A FLAT SUPPORT MEMBER HAVING A SUBSTANTIALLY RECTANGULAR CROSS-SECTION AND PROVIDES WITH A FIRST SURFACE, A SECOND SURFACE AND OPPOSING SIDES, AN ELECTRICAL CONDUCTOR MEANS HAVING A FIRST PORTION AND A SECOND PORTION, SAID FIRT PORTION BEING IN ENGAGEMENT WITH SAID FIRST SURFACE, AND A FERRULE MEMBER HAVING A FIRST SECTION IN SNUG ENGAGEMENT ALONG SAID SECOND SURFACE, SIDE SECTIONS EXTENDING ALONG RESPECTIVE SIDES AND A SECOND SECTION EXTENDING INWARDLY TOWARD SAID FIRST SURFACE AND SECURING SAID FIRST PORTION OF SAID CONDUCTOR MEANS THEREBETWEEN WITH SAID SECOND PORTION EXTENDING OUTWARDLY FROM SAID FIRST PORTION, SAID SIDE SECTIONS HAVING FIRST AND SECOND DEPRESSIONS AT SPACED INTERVALS THEREALONG WITH SAID SECOND DEPRESSIONS BEING DISPOSED BETWEEN SAID FIRST DEPRESSIONS, SAID DEPRESSIONS BEING DIRECTED INWARDLY TOWARD SAID OPPOSING SIDES OF SAID SUPPORT MEMBER THEREBY SECURING SAID FERRULE MEMBER ON SAID SUPPORT MEMBER. 